You may want to think twice before taking a dip on your next vacation, according to the results of a new report from the Centers for Disease Control and Prevention (CDC).

Between 2000 and 2014, the CDC recorded 493 disease outbreaks related to treated recreational water, resulting in more than 27,000 illnesses and eight deaths. And in almost a third of those outbreaks, the infections could be traced back to hotel pools, hot tubs and spas, the CDC says. In hotels, pools were a major culprit, but 65 cases stemmed from hot tubs or spas.